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Complete Home Automation from Multiple Devices

extender i2c spi ethernet

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#1 grantdennison

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Posted 05 September 2013 - 02:30 PM

hello, first post

 

experience = python average, c# little(but want to do most programming in c# for future jobs)

                     electronics good (want to build most circuits)

 

I'm building a complete home automation. The problem I'm having is getting all the info from multiple devices around the House. Some devises can be 10-15 meters away. Wont be much info mainly just high's and low's to turn things on/off and check states. Each room will have properly have 8 devises+ and maybe more in the future.

So i don't want hundreds of cables all over.  So i need a data bus of some sort.

 

My dream would be using cat cable that i can plug into netduino plus 2 (master), than plug into slaves all over the house so therefore only one cable will run round the house. Them when i use visual studio i can see address slave and pins on the slave.

 

I am considering i2c (but heard its really hard), spi (but limited need more wires)

 

i2c looks like cheapest with this chip [color=rgb(51,51,51);font-family:Trebuchet, 'Trebuchet MS';font-weight:bold;]MICROCHIP MCP23017-E/SP DIP28.[/color]

 

or using arduino think will be the easiest having theses in each room

[color=rgb(51,51,51);font-family:Trebuchet, 'Trebuchet MS';font-weight:bold;]New W5100 Ethernet Shield + Arduino mega[/color]

 

[color=rgb(51,51,51);font-family:Trebuchet, 'Trebuchet MS';font-weight:bold;]I would prefer to use ethernet/lan so I can learn something that might help with future jobs.[/color]

I not looking to spend too much.

 

Any guidance on the best way to connect devices will be appreciated.

 

Thank's  Grant



#2 mcinnes01

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Posted 05 September 2013 - 10:07 PM

I am on the same quest as yourself currently....

 

Although I am running about 140 separate runs of cat5e.

 

Some will have wall plates (phone, ethernet) some go to devices, sensors, valves, switches, etc.

 

This all goes back to a patch panel so I can route and change the use as and when I want.

 

Also worth thinking about POE.

 

As I have recently learnt from Mario, SPI is not good over long distances and I have had flakey experiences with it in the past. Noise is a real issue.

 

This is true with i2c but to less of an extent and there are ways of reducing noise and its effects.

 

Something to perhaps ponder, to reduce the effects of resistance you will probably want to step your signal up to say 24v. This in itself creates noise and other complications, but solves the issue of running over long distances.

 

I will share what I learn from Mario and perhaps you can share your ideas?

 

Andy



#3 grantdennison

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Posted 06 September 2013 - 05:03 AM

wow thats impressive 140 runs. Thanks for the info more to think.

Quick questions on your setup?

  • Are all the runs going to one central location or are you using splitters at points(eg so one cable to a light splits off to another light) or does each device have its own run back to base. If you didn't split cable is there a reason.
  • What connection are you using at each device to convert ethernet to control lights,motore ext.

It's amazing how many different ways there are to do this, almost wish there was a standard.

 

Thanks Grant



#4 mcinnes01

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Posted 06 September 2013 - 10:45 PM

I am having 2 central locations, 1 in the loft and 1 in the cellar to avoid having to create a riser and to reduce cable runs. I will have a gigabit link between the 2 and am installing a 96 port patch panel in each to allow me to route things ad-hoc.

 

Each light will go back to these 2 points where I will have a distribution board. Relays will perform the switching all located centrally on the 2 distribution boards. This makes maintenance easy and reduces the number of points of failure. In house having a single or couple of points of failure is desirable as it means you don't have to start ripping up walls and floor boards.

 

Although CAT5 is going in, I may in most cases just use it for the the shielded twisted pairs. As there are 4 pairs you can send data and power down the same cable without creating too much noise. Also if you change your mind you can convert them to standard cat5 cables.

 

Check out some of my active threads for ideas.

 

Andy







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